DAF 46 rear brake adjustment

[dafix]

Hello,

I have just adjusted the parking brake of my DAF 46 (it was quite loose). As my maintenance manual is not extremely accurate on the topic and I am not a skilled mechanic, here is the procedure I used after some try-and-errors (if someone is interrested0:

- Pull the rubber sleeve of the brake lever forward (toward the release button) to have access to the screw and the nuts, attach the sleeve to the lever with a rubber band.

- Jack up the rear of the car (using as jacking point the center of the tube of the de Dion axle).

- From the fully released position, lift the lever by 5 notches.

- Tip over the driver seat (as for getting access to the backseat) to have better access to the nuts.

- Loosen the lock nut with a 10-mm spanner/wrench ("clé anglaise" in french ) while holding the adjusting nut (below the lock nut) with a spanner/wrench of the same size. This may not be easy as the standard tools are a bit too thick to hold both nuts separately. Spraying WD-40 on the screw a day before may also help.

- Plunge a flat screwdriver through the hole at the top of the lever to hold the screw (insert the screwdriver in the slot at the top of the screw).

- While holding the screwdriver, turn the adjusting nut clockwise. Check that the rear wheels cannot be turned by hand. Repeat until it's done.

- Tighten the lock nut.

- Put back the sleeve, jack down the car.

Here is what the lever looks like during the adjustment (bad picture quality but I hope it may help):

Now, I have felt that the brake is stronger on the left side that on the right side. I already noticed when I drive that if I brake firmly, my DAF 46 tends to drift to the left side. I still have to adjust the front wheel parallelism to have the toe-in within the specs, but I think I will have anyway to adjust the balance of the rear brakes. My manual specifies there are brake "adjusters" to be tuned using a "special tool 267066" but I have no idea how these adjusters and this tool look like. A picture showing them would be welcome.

[andrew]

I hope the following will help: I think you may have done things in the wrong order, since when I worked in a garage and a car had a problem with the handbrake the first thing we looked at was the adjustment of the footbrake. The handbrake lever pulls on one of the rear shoes, to hold the car. If the footbrake isn't adjusted properly the handbrake has to move the shoes further before they can grip the drum; this is reflected in greater movement in the handbrake lever when you pull it on. The adjustment you have made is only to tighten the cable when it has stretched.

I'm currently carrying out a load of work on my 33's brakes (they're in a bit of a state...) and I can confirm that merely by adjusting the brake shoes the handbrake became much more effective!

[dafix]

Hi Andrew, thank you for your hint. Yes, I need anyway to adjust the footbrake on the rear wheels (which probably means that I have to adjust the gap between the shoe lining and the drum for each wheel when the brake is not activated) because of this dangerous tendency of my DAF to drift to the left side, but I don't know how to proceed yet. Once done, I can again re-adjust the handbrake (now that I know how to do it, it should not be difficult). I had noticed for a long time that when parking on a slope I had to pull the lever quite high and strongly to avoid to slip, that's why I wanted to adjust the lever.

[andrew]

If you really want to adjust the brakes you should remove the drums and take a look at the shoes. It's important to check they're not too worn and, perhaps more importantly, that they're not unevenly worn. Again, to make a really good job of it, the adjusters should be removed and cleaned up, before being given a thin coating of anti-seizing grease. Once the drum is back on the hub you should then adjust the shoes. We used a phrase to explain how one did this, but it's not particularly polite, so I'll not use it... Only THEN should the handbrake cable be adjusted, if it's then necessary.

If you need more advice, just ask!

[starider]

Hi, I agree with what Andrew has said,but if your car drifts to one side on braking I am fairy sure it's not the hand brake.I strongly advise removing all the drums[front and rear]. It's amazing what can cause drifting under braking:- a leaking wheel cylinder,worn brake linings,siezed wheel clinders,loose wheel bearings,brake dust in the drums,wrong tyre pressure,tracking[we spent a whole day once trying to cure a DAF pulling to the left on braking, eventually in sheer desperation we swapped the wheels from on side to the other,amazingly problem solved,nver did find out why!!}. I personally would look at the fronts first.Remember the 46 has a split hydraulic system i.e.if I remember correctly the system[master cylinder] operates front o/side and rear n/side and visa versa.The reason is that as a safety feature if one 1/2 the brake system fails the other will still allow braking.
I think the first job should be to slacken off the hand brake cable!
As Andrew said,don't be afraid to ask,there is a wealth of experience within the club.

[gromsound]

daf brakes are at most front-rear split, the 46 too. Big OVLOVs did have the diagonal (in fact triangular) split.
Is there no more CT (MOT) in france? Your car will definitely fail the brake balance test...
Indeed mostly due to one seized wheel cylinder or even a leaking one.

The ''special brake adjusting tool'' is just a key for square pegs, cheap thing from your local ironshop. If the adjusters are not rusted solid, a normal key will do fine (was it 8 mm or 10? i've got too much dafs...).

And indeed first adjust the shoes, then adjust the handbrake cable, you may even run into trouble if the cable is now too tight for the shoes to move freely to the inner position.

PS in Holland the adjustable wrench is also called 'engelse sleutel' = english key ! But normally we call it a Bahco (original brand name).

[dafix]

Hi,

The last CT reported a 19% unbalance between the two rear brakes (forces were 153 daN on the left, 124 daN on the right), just below the 20% limit. I have found the adjusters (square heads at the bottom of the brake plates). I made a tool using a 1/4"-to-5mm socket connected to a sacrificed 5-mm Allen wrench from an Ikea furniture that I cut at the end (so the tool can be inserted between the brake and the retaining bracket of the leaf spring). I expected to feel or to hear a clicking (like a ratchet) as I moved the tool on the rear-right adjuster, but nothing. I could turn the adjuster until blocking the wheel, then I released a bit to free it. Hard to tell if it's good or not. Then, I had a ride for test, mostly on empty roads, trying to brake hard and the behavior seems to have improved: I didn't notice any drift to the side. Anyway, I will see the report of the next CT to get precise figures. If the brakes are not compliant, I will see if I dare to work on them or if I ask a professional. By the way, anyone knows the OEM of DAF46 brakes ? Was it Girling (because of the use imperial units) ?

[andrew]

Just a thought.... Was the imbalance the the handbrake or the footbrake or when both were tested? Only this morning have if finally managed to remove the cylinder from one of the backplates of my 33. The fittings were all imperial; 1/2 inch spanners, 7/32 inch Allen keys and 9/16 inch on the flexible brake pies. Amazing to think that a vehicle designed and built in Holland has Imperial fittings. I did think (as I lay beneath the car this morning.......) that the brakes were not efficient enough to satisfy the U.K. construction and use regulations back in the 1960s. At that time the United Kingdom was not part of the (then) Common Market (as, indeed, we are not now) and maybe the U.K. importers were obliged to alter the brakes in some way to increase their efficiency, in order to meet the standards required.

As for working on the brakes-yes, go (or should that be stop?) for it and we will all chip in with advice!

[gromsound]

The 33 brakes date back to the first 600 in 1959 and are identical to the original Mini: Lockheed all around. No mystery there, Daf just bought something existing from the shelf (and along the way heard from Lockheed that there was a BMC product coming up with the same drum diameter). It is generally understood that they are rather weak for the heavier Daf. Keep your distance from the car in front of you.

The 46 has most probably the same rear brakes as the last 66es (L version with drums up front) which were Girling ones. You should be able to see it written on the triangular master brake cylinder reservoir. It would be easy to swap the rear brakes (everything with the brake plates) for 66 SL/marathon/V66 ones that are self adjusting using a small built-in ratchet system that clicks further with increased wear of the linings thus keeping the distance to the drum constant.

The shoes are the same so brake balance F/R would not be changed.

Regarding UK spec, the 66 parts manual states for Girling rear wheel brake cylinders (same as 46 btw, daf part no 266305) two different diameters:

LHD = 0.625, RHD = 0.812 (inches?). We have the first version which is 15.875 mm. So there seems to be a different spec indeed. Maybe because of more hills in your country?

[starider]

Hi Andrew, not sure how much of the brakes you are replacing, I had a real problem finding new front wheel cylinders[with the larger bore],there was quite a lot of discussion[2011 I think]about fitting larger bore cylinders to improve braking and 3/4" bore was quoted. My van had been up rated to 7/8" bore. These were difficult to source but eventually found a pair. If you want the part number let me know. I ordered them from up north,I'll try and find the suppliers details. I received them within 24hrs. Don't forget you need the special tool to fit the new retaining clip.If you haven't got one, there are 2 suppliers on ebay. Go for the cheaper one,about £9-50 I think.

Tony

[andrew]

Tony,

I'm replacing all the cylinders, as they are weeping. While doing so I'm replacing the shoes, since they've worn unevenly. The rear brakes are easy, sine they're an exact copy of early Mini ones, cylinders, shoes and all. I even have a set of asbestos shoes, so they must be quite old! The front ones have proved more problematic....

Both front and rear cylinders have a small locating pin, which locates them precisely onto the back plate. On the rear ones this pin is exactly in line with the bleed nipple, but on the front ones it's slightly lower, so the cylinders are not interchangeable. I could remove this pin and rely on the nipple to locate the cylinder, but I wouldn't be happy with this. I've been unable to find ANY of these cylinders anywhere, so am having the ones from the car refurbished by a company in Ipswich, so they'll be as good as new once this is done. I've removed the front backplates and have cleaned them, painted the outside in Hammerite white and treat the adjusters with anti-seize grease.

Another intriguing thing I found when dismantling the brakes was that the top spring (nearest the adjuster) on both rear brakes was doing nothing. The spring was "flapping around" (for want of a better expression) inside the drum, which explains the uneven wear to some extent. I'm aware that drum brakes wear to a greater extent at one side, and I know some unscrupulous garages have been known to simply reverse them, to even out the wear. I suppose this isn't too bad, as long as the owner knows that's happened and is prepared to check the shoe wear regularly.

I'll be extending the brake pipes at the rear, by adding a short length of flexible brake hose between the cylinder and the end of the fixed pipe, so that, should the half-shaft snap again I'll not have to bleed the brakes!

Any ideas, thoughts or advice welcome.....

[starider]

Hi Andrew, It's possible someone in the past had not hooked the spring in the correct hole in the shoes.When I replaced the brakes on the van someone had,previously,fitted the "split spring" upside down which had meant the centre part of the spring had nearly worn through by rubbing on the hub.
Just a couple of notes to everyone,when fitting new brake shoes make sure you file the edges of each brake lining to produce a chamfer of approx. 2mm-3mm, this allows for any slight difference in the new friction material width. It's also a good practice to put a large chamfer on the leading edge of each shoe i.e. the part of the shoe which contacts the drum first when the brake is operated.
Finally it's important to note that any classic vehicle which has drum brakes all round ,will need upto 100 miles driving before the brakes reach optimum performance. Disc brakes need roughly the same but due to the superior efficiency of discs the initial efficiency is far greater than drum brakes.
The way braking systems are designed the braking percentage should be around 75% front brakes 25% rear.
When I was a motor cycle instructor[many,many years ago],I used to demonstrate the efficiency of braking.I would set up a couple of cones as a "gate",stand the trainees some distance away,then ride my bike at 30mph, when I reached the "gate" I would apply the rear brake as in an emergency and ask a trainee to put a cone in line with the front wheel spindle.Do the same again with just the front brake,and finally again using both brakes[the front fractionally before the rear].Obviously the rear was the least efficient, the front being far the more efficient of the two, and the correct use of both brakes produced the correct result.What was interesting was that the distance from the gate cones to each of the braking marker cones was almost the same.

[Richard DAF Webmeister]

*Blatant plug warning!*

We have an interesting article about a special tool to do with brakes, in the next magazine, which is on its way from the printers very soon.

[bobdisk]

Andrew, and Starider, have you seen these people for classic Mini parts, including brakes.

www.minispares.com/shop/classic/Brakes.aspx?04

www.minispares.com/shop/classic/Brakes/Hydraulics/Wheel~Cylinders.aspx?041002

It seems that the position of the locating pin (Offset for rear, in line for front)   indicates the position of the cylinder, (for early Minis that also used the same one leading/one trailing arrangement with a pressure limiter as the Daf 33) , (so might also indicate the piston diameter ? and hence the operating pressure,) so the correct one must go on the correct end, front or rear.
When I first got the Daf, I was surprised to find that the front and rear brakes both had one leading and one trailing shoe arrangements. I remember my first car, a 1959 Morris 1000, and others with front drum brakes, had both front shoes leading, and one leading and one trailing rear shoes. This resulted in a more efficient front brakes compared to the rear. Daf and early Minis get this difference by using a pressure limiter in the rear circuit, but its not as effective, but is cheaper than the twin leading shoe arrangement.

[starider]

Hi, yes when looking for new wheel cylinders I tried all the Mini parts specialists who like everyone else I tried had rear cylinders in stock and my trade spares supplier spent hours trying to locate the 7/8" bore front cylinders.Luckily quite by chance I came across a supplier.